This invention relates to a passive three-point safety harness for use in a motor vehicle and more particularly relates to a three-point safety harness which has an arrangement to guide the safety belts that form the harness.
A typical passive three-point safety harness for use in a motor vehicle comprises two safety belts each with its own retractor mechanism or reel. One safety belt is to form a chest or shoulder belt and the other is to form a lap or waist belt. Both the retractor mechanisms are located on the side of the seat which is furthest from the associated door of the motor vehicle. The free end of the lap belt is secured to a mounting provided on the interior of the door of the vehicle which is located adjacent the relevant seat. The free end of the chest or shoulder belt is secured to a mounting which is movable along a rail mounted in the roof of the vehicle extending over the door opening.
A passive three-point safety harness, of the type described above, is constructed and arranged so that, when the door of the vehicle closes after a person has sat on the seat, the various safety belts are automatically positioned to extend across the lap and across the chest of the person sitting on the seat, with the mounting of the chest or shoulder belt being moved along the rail. The harness will then restrain the person in the seat in the event that an accident arises. However, the harness is also arranged to "open" or withdraw from the person sitting on the seat automatically in response to a certain signal, for example when the vehicle door opens.
The free end of the lap belt is often secured to a mounting which is movable along a rail or track mounted on the inside of the vehicle door, the mounting being adapted to move along the rail when the door opens and closes in a similar manner to that in which the mounting of the end of the shoulder belt on the rail provided in the vehicle roof is displaceable along the rail. It will be appreciated that when the mountings are each at one end of their respective rails the harness is in the "closed" state in which it embraces and retains a person in the vehicle seat, and when the mountings at the opposite ends of their respective rails, the harness is "open". The movements of the mountings are controlled by an appropriate mechanism which is adapted to be actuated, for example, in response to opening and closing of the door of the vehicle, or in response to the switching on or off of the ignition.
The problem that has arisen in prior-proposed three-point safety harnesses of the type discussed above is that when the harness is in the "open" condition the lap belt is either lying on or extending immediately above the seat. This makes it difficult for a person to enter into the vehicle, since the person must lift up this portion of safety belt as the person climbs into the vehicle.
Prior proposals have been made to overcome this particular problem. One example of such a prior proposal is disclosed in DE-OS 2260243, which discloses the use of a special arm which holds up the lap belt when the harness is in the "open" condition. However, such an arm is expensive to produce and assemble, and also takes up a considerable amount of space in the motor vehicle. It is also known to use an arrangement which effectively lifts the lap belt, this being in the form of a hoop or ring which is secured to a fixed position to the shoulder belt, and through which the lap belt can extend in a sliding manner. Arrangements of this kind are described in DE-OS 2260243 and DE-OS 2263291. These harnesses do raise the lap belt in a satisfactory way when the harness is "open" but have the disadvantage of fitting only a person of a particular size when the harness is "closed". If a smaller person occupies the seat the chest or shoulder belt is insufficiently tensioned since the hoop or ring which is connected to the shoulder belt prevents the belt from being retracted sufficiently into the reel, while if a larger person sits on the seat the hoop or ring contacts the body of that person and may cause irritation.
U.S. Pat. No. 3 889 971 discloses another similar arrangement, but in this arrangement the retractor reel for the lap belt is mounted on the door, and is not mounted on the side of the seat which is furthest from the associated door of the vehicle. This Specification discloses the use of a ring which serves to combine the two belts at their middle portions but provides no teaching as to the nature of the ring.